Electric heating apparatus



R. P. DUNNING.

ELECTRIC HEATlNG APPARATUS.

APPLICATION FILED JUNEZl, 1920.

Pata znted Dec. 21, 1920.

0 Z 4 Z Z Z 0 4 a "WWW a \W wmwzwu Ill 0 M lrwagtor: Ra gmoh z Dunning,

His Attorney.

UNITED STATES PATENT .OFFICE.

RAYMOND I. DUNNING, OI BCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC-TRIO COMPANY, A CORPORATION OF NEWYOBK.

ELECTRIC HEATING APPARATUS.

Specification of Letters Patent.

Patented Dec. 21, 1920.

Application filed June 21, 1920. Serial No. 390,519.

, is a specification.

My invention relates to an electric heating apparatus and'particularlyto a device adapted to heat articles such as rivets and the like bypassing current therethrough in series.

An object of my invention is to provide a simple and compact devicewhich shall provide a plurality of circuits for heating articles inseries and which shall be capable of ready adjustment independently tocontrol the current in the various circuits whereby articles ofdifferent size and cross section may be simultaneously heated on thesame machine.

My invention will be better understood from the following descriptiontaken in connection with the accompanying drawing, and its scope will bepointed out in the appended claims.

Figure 1 is a perspective view of an electric heating device embodyingmy invention; and Fig. 2 is a diagrammatic view representing the circuitconnections of the device shown in Fig. 1.

Referring to Fig. 1, a shell-type transformer is illustrated providedwith primary windings 1 and 2 wound on the outside legs of the core, thecenter leg 3 being left unwound. Electrodes lr, 5, 6 and 7 are mountedrespectively on conducting bars 8, 9, 10 and 11 preferably made ofcopper, which are mounted for pivotal movement upon a rod 12 secured tobrackets 13 mounted upon the supporting framework. This frameworkcomprises front legs 14, 15, rear legs 16, 17 and suitable bracingmembers. The conducting bars 8 and 9 are electrically connected togetherat the rear by a flexible laminated conducting member 18, and a similarconducting member 19 connects the bars 10 and 11. The pairs of bars 8and 9 being in inductive relation to the primary winding 2, form asecondary winding for this primary winding and the bars 10 andlllikewise form a secondary winding for the primary winding 1. Thesecondary circuit comprising the bars 8 and 9 is adapted to be completedin series through the articles 20 to be heated interposed between theelectrodes 4. and 5 and the conductlng member 21. In like manner thecircuit of the secondary winding comprising bars 10 and 11 is adapted tobe completed in series through .the articles interposed between theelectrodes 6 and 7 and conducting member 22. The conducting members 21and 22 are supported on the adjustable member 23 mounted on thesupporting frame of the device. Insulating locks 24. are provided toinsulate the conducting members from the supporting member 23. Anyconvenient means may be used to raise and lower the movable electrodesto permit of ready insertion and removal of the articles to be heatedand in the drawmg a foot lever 25 is shown connected to each of the bars8, 9, 10 and 11 through rods 26 in which insulating joints 27 areinterposed. n

Fig. 2 shows the circuit connections to the primary windings 1 and 2 ofthe transformer, the bars 8, 9, 10 and 11 comprising the secondarywindings being shown in section. Means indicated as a switch 28 isrovided in the circuit of the primary win ing 1 for adjusting the numberof turns thereof I and a similar switch 29 is provided for varying thenumber of turns of the primary winding 2. The windings 1 and 2 are shownas supplied in parallel from any convenient source of alternatingcurrent represented by the mains 30. I preferably arrange thetransformer windings so that when the same number of turns are used ineach of the windings 1 and 2, no flux flows in the middle leg 3 of thetransformer core. With this adjustment the electromotive force inducedin the secondary winding comprising the bars 8 and 9 is equal to theelectromotive force induced in the secondary winding comprising the bars10 and 11. With this adjustment, it is apparent that the device isadapted to heat articles of the same size and cross section in each sideof the device. ent, however, that the arrangement of windings upon thecore permits of independently adjusting the number of turns andmagnetomotive forces in the respective primary windings 1 and 2, sinceflux may flow in the leg 3 equal to the resultant or unbalanced fluxwhen the transformer primaries are given difi'erent adjustments. Thismakes it pos.

sible simultaneously to heat articles of one size in one side of thedevice, while articles of It is appara different size are heated in theother side of the device, the heating current being adjusted to the bestvalue for each size of article.

While I have shown one particular embodiment of my invention, it will beapparent to those skilled in the art that various modifications andvariations may be made therein, and I desire to cover all such changesas fall within the scope of my invention, which is defined in theappended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,-

1. An electric heating apparatus of the class described comprisingamagnetic core having a plurality of legs, primary windings arranged uponsaid legs, secondary windings arranged in inductive relation to each ofsaid primary windings, electrodes connected to said secondary windingsand arranged to engage and supply heating current to the articles to beheated, means whereby the number of turns in said primary windings maybe independently adjusted and means on said core providing a path forunbalanced fluxes in said core legs.

2. An electric heating device of the class described comprising ashell-type transformer having a primary winding on each of the outerlegs, secondary windings each comprising a pair of conducting barsmounted in inductive relation to each of said primary windings,electrodes carried by said conducting bars arranged to engage and supplyheating current to the articles to be heated.

3. An electric heating apparatus of the class described comprising ashell-type transformer having a primary winding on each of the outerlegs, means for independently adjusting the magneizing effect of saidwindings, secondary windings for said primary windings comprising aplurality of conducting bars arranged in inductive relation to saidprimary windings, and electrodes carried by said conducting barsarranged to enga e and supply heating current to the artic es to beheated.

4. An electric heating apparatus of the class described comprising ashell-type transformer having a primary winding on each of the outerlegs, means for independently adjusting the number of turns in saidwindings, secondary windings for said primary windings comprisingindependently movable conducting bars mounted in inductive relation tosaid primary windings, electrodes carried by said conducting bars,stationary electrodes between which and the said movable electrodes thearticles to be heated are adapted to be interposed to complete circuitsfor said secondary windings in series through a plurality of articles tobe heated.

In witness whereof, I have hereunto set my hand this 18th day of June,1920.

RAYMOND P. DUNNING".

